Electric machines have power limitations due to the overheating of internal components. In conventional systems, electric machines are often cooled via exterior cooling. For example, heat sinks may be provided on the external surface of an electric machine to assist with cooling. In some examples, fluid may flow through an outside enclosure of an electric machine or over an external surface of the machine. See, e.g., U.S. Pat. No. 7,550,882; U.S. Pat. No. 5,939,808; U.S. Pat. No. 5,670,838; and U.S. Pat. No. 4,700,092, which are hereby incorporated by reference in their entirety. In some instances, fluid may be provided within an electric machine to assist with cooling, but may be contained within the machine. See, e.g., U.S. Pat. No. 4,644,202; and U.S. Pat. No. 7,352,090, which are hereby incorporated by reference in their entirety.
With improved cooling and lubrication of internal components, it is possible to design an electric machine to produce high power in a much more compact and lower weight package as compared to traditional machine designs. The improved cooling and lubrication facilitates increasing the operating current and speed of the machine, which translates directly into higher torque, higher power, and consequently higher power density.
Thus, a need exists for improved electric machine systems and methods, which may utilize fluid that may flow internally through an electric machine for cooling and lubrication.